UL 94 – Flame Rating – 5VA
UL 94 flame classifications
There are 12 flame classifications specified in UL 94 that are assigned to materials based on the results of these small-scaleflame tests. These classifications listed in descending order for each of the following three groupings are used to distinguish a material’s burning characteristics after test specimens have been exposed to a specified test flame under controlled laboratory
- Six of the classifications relate to materials commonly used in manufacturing enclosures, structural parts and insulators found in consumer electronic products (5VA, 5VB, V-0, V-1, V-2, HB)
- Three of the remaining six classifications relate to low-density foam materials commonly used in fabricating speaker grills and sound-deadening material (HF-1, HF-2, HBF)
- The last three classifications are assigned to very thin films, generally not capable of supporting themselves in a horizontal position (VTM-0, VTM-1, VTM-2). These are usually assigned to substrates on flexible printed circuit boards.
UL94 5VA & 5VB Flammability Standard
Bars: Length 125 mm (5 in) x Width 13 mm (0.5 in) x Thickness [typically 3.0 mm (1/8 in)].
Plaques: Length 150 mm (6 in) x 150 mm (6 in) x Thickness [typically 3.0 mm (1/8 in)].
Procedure for Bars
A total of 10 specimens (2 sets) are tested per thickness. Five specimens of each thickness are tested after conditioning for 48 hours at 23 degrees C and 50% RH. Five specimens of each thickness are tested after conditioning for 7 days at 70 degrees C.
For bar specimens, the specimens are mounted with the long axis vertical. A 125 mm overall high Bunsen burner flame with a 40 mm blue inner cone is applied to the lower corner of each specimen at an angle of 20 degrees from vertical such that the tip of the blue inner cone touches the specimen. The flame is applied for 5 seconds and removed for 5 seconds. The operation is to
be repeated until each specimen has been subjected to 5 applications of the test flame.
Procedure for Plaques
Same as for bars except that the plaques are to be mounted on the horizontal plane with the flame applied to the center of the bottom surface of the plaque.
Requirements for 5VA
The specimens may not burn with flaming or glowing combustion for more than 60 seconds after the fifth application of the test flame. The specimens may not drip flaming particles that ignite the dry absorbent surgical cotton located 300 mm below the test specimen. Plaque specimens may not exhibit burnthrough.
Requirements for 5VB
The specimens may not burn with flaming or glowing combustion for more than 60 seconds after the fifth application of the test flame. The specimens may not drip flaming particles that ignite the dry absorbent surgical cotton located 300 mm below thetest specimen. Plaque specimens can exhibit burnthrough.
Before using this product, the user is advised and cautioned to make its own determination and assessment of the safety and suitability of the product for the specific use in question and is further advised against relying on the information contained herein or previously represented as it may relate to any specific use or application. It is the ultimate responsibility of the user to ensure that the product is suited and the information is applicable to the user’s specific application. ATTABOX LLC does not make, and expressly disclaim, all warranties, including warranties of merchantability or fitness for a particular purpose, regardless of whether oral or written, express or implied, or allegedly arising from any usage of any trade or from any course of dealing in connection with the use of the information contained herein, previously represented or the product itself. The user expressly assumes all risk and liability, whether based in contract, tort or otherwise, in connection with the use of the information contained herein, previously represented or the product itself. Further, information contained herein or previously represented is given without reference to any intellectual property issues, as well as federal, state or local laws which may be encountered in the use thereof. Such questions should be investigated by the user.